Two-cycle internal-combustion engine.



, D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV. 27.19I2. LI'FQQBQQ, Patented Feb. 22, 1916.

4 $HEETSSHEET I.

D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV-27.1912. 1,172,324, Patented Feb. 22,1916.

4' SHEETS-SHEET 2.

fiiiorncy D. M. TUTTLE.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED NOV.Z7,19I2.

Patented Feb. 22, 1916.

4 SHEETSSHEET 3.

Jnv n r Wiines e5 D. M. TUTTLE.

TWO-CYCLE INTERNAL comsusnow ENGINE. APPLICATION FILED NOV. 27. I912. 1172 324. Patented Feb. 22,1916.

4 SHEETSSHEET 4- rrnn erm ne PATENT GFFIQQ DANIEL M. TUTTLE, OFCANASTOTA, NEW YORK, ASSIGNOR TO STELLA S. TUTTLE, OF CANASTOTA, NEWYORK.

TWO-CYCLE INTERNAL-COMBUSTION ENGINE.

Application filed November 27, 1912. Serial No. 733,870.

To (ZZZ whom it may concern:

Be it known that I, DANIEL M. TUTTLE, of Canastota. in the county ofMadison. in the State of New York, have invented new and usefulImprovements in Two-Cycle Internal- (lombustion Engines, of which thefollowing, taken in connection with the accompanying drawings, is afull, clear, and exact description.

This invention relates to certain improvements in two-cycle internalcombustion engines of the class set forth in my pending applicationsNos. (360,834 filed November 17, 1911. and 6 54.760 filed August 18,1911, in which the cylinders are provided with valvecontrolled intakeand inlet ports and pistoncontrolled exhaust ports, said cylinders beingarranged in pairs and provided with a constantly open passage connectingthe valve chambers of the intake valves with those of the inlet valvesfor the purpose of reserving a quantity of the explosive mixture underpressure at both of the inlet valves, such pressure being sufficient tohold the inlet valve of each cylinder open some time after the exhaustport of such cylinder has been closed by the compression stroke of thecorresponding piston.

This constantly open passage serves to materially increase the powereiiiciency of the engine, but I have discovered that. even under thesefavorable conditions. the high degree of pressure exerted upon the inletvalve when it opens, allows the infiowing charge to enter the firingchamber with such force as to drive it rapidly toward the bottom of saidchamber and to the exhaust port and thereby produce an undesirablemixture with the burned gases which incidentally lowers the possiblepower efficiency of the engine.

The main object therefore is to reduce this excessive initial pressureand to render such reduced pressure more equal and constant at the inletso that when the inlet valve is open the new charge will not enter withsuch rapidity and force as to produce an objectionable mixture with thespent gases or escape at the exhaust but on the contrary will collect ina more compact mass in the head of the firing chamber and moreeffectively expel the burned gases while the exhaust is open therebyobtaining a more powerful mixture and assuring a more posi-Specification of Letters Patent.

Patented Feb. 22, 1916..

give ignition without skipping or missing Another object is to increasethe advantages of the reduced and equalized pressure by baffling thedirect passage of the inflowing charge to the exhaust and therebyincreasing its compactness and ability to expel the spent gases at theproper time without mixing therewith.

A further object is to obtain a greater power efficiency inmulti-cylinder engines by arranging such cylinders in pairs andconnecting their intake ports and inlet ports in such manner as tomaintain a constant pressure of the inflowing mixture upon the inletvalves tending to hold such valves open after the exhaust ports of eachcylinder are closed by their respective pistons, thereby permitting ahigher degree of compression ofa greater quantity of the explosivemixture in the firingchamber than would be possible if the inlet valveswere closed simultaneously with or before the closing of the exhaustports as usual in two-cycle engines.

()ther objects-and uses will be brought out in the followingdescription.

In the drawings, Figure 1 is a side elevation, partly in section, of atwo-cycle fourcylinder engine embodying various features of myinvention. Figs. 2 and 3 are transverse vertical sectional views of thesame engine taken respectively on lines 22 and 3-43. Fig. 1. Fig. 4 is alongitudinal vertical sectional view of a two-cylinder engine of thesame type showing a modified ar-' rangement of the connecting'passagebetween the valve chambers for the intake and inlet valves. Figs. 5 and6 are transverse vertical sectional views taken respectively on lines5-5 and 66, Fig. 4. Fig. 7 is a detail sectional view of the upperportion of one of the cylinders showing a slightly modified form ofretarding flange for the infiowing mixture. Fig. 8 is a longitudinalvertical sectional view of a modified form of 1)ressure-equalizingchamber having branches connected directly to the valve chambers for theintake valves. F ig..9 is a transverse vertical sectional view throughthe pressureequalizers shown in Fig. 8.

The engine shown in Figs. 1. '2 and 3 comprises a series of fourcylinders, 1, -2-. 3- and 4, arranged side by side in pairs and providedwith pistons 5 which are connected by suitable pitmen -6 to a crankshaft -7, the crank arms of the shaft being arranged on the quarter turnrelatively to each other. That is, the crank arms corresponding to eachpair of cylinders are diametrically 0pposite, so that when the pistonsof one pair of cylinders are at the limit of their strokes at oppositeends thereof, the pistons of the other pair of cylinders will be on thehalf stroke but moving in opposite directions. The cylinders aresubstantially identical in form and size and each is provided with afiring chamber 8 and a coaxial compression chamber 9 of greater crosssectional area than the firing chamber,.while each of the pistons 5comprises a main body 10 of substantially the same diameter as andmovable within the firing chamber 8 and a coaxial compression head -11of substantially the same diameter as and movable within the compressionchamber 9. The object of these differential sized portions of thecylinder and piston is to produce a higher degree of initial compressionof the mixture admitted to the compression chamber preparatory toexpulsion into the firing chambers. These features, however, are clearlybrought out in my pending applications above referred to and, therefore,need not be more fully described in this case. Each cylinder is providedwith an intake port -12, an inlet port 13 and an exhaust port 14.'.

The intake port -12, which is connected in the manner hereinafterdescribed to a suitable carbureter (not shown) communicates with theinner end of the compression chamber 9 and is controlled in thisinstance, by a rotary valve 15 external to the cylinder.

The inlet ports 13 which are preferably located in the heads of thecylinders and communicate with the firing chambers, are controlled bypuppet valves -16 and, as shown more clearly in Figs. 2 and 3, are inconstant communication with the valve chambers for the valves 15 throughsuitable conduits or passages 17.

The exhaust ports -14- of the several cylinders are located,- as shown,near the outer ends of the firing chambers and are controlled by theirrespective pistons 10-, said exhaust ports being connected by a suitablemanifold 18.

The valves 15 for the several intake ports 12 are coaxial with andconnected for simultaneous rotation by any suitable driving mechanism(not shown but capable of synchronizing the movement of said valves withthat of their respective pistons.)

Each valve chamber for the valve 15- is provided with a series of, inthis instance three, ports, .-19, -20 and 21.

r which are connected respectively to the carbureter (not shown), theintake port l2 and the corresponding conduit 17 as shown more clearly inFig.

Each of the valves 15 is provided with diametrically opposite transverserecesses 22- and 23 adapted to alternately and successively connect theport 20 with the ports 19- and 2l, said valve being so timed as toconnect the ports 19 and .-20 and thereby establish communicationbetween the carbureter and intake port during the out-stroke of thepiston and then to connect the ports 20- and 2l during the compressionstroke of such piston so as to establish communication between theintake port and the inlet ports of'both cylinders through the passage orconduit 17- tending to open the valves 16 against the action of suitableretard- 111g springs 24. by which said valves are automatically closed.At about the time or just after the piston has reached'the limit of itscompression stroke, during which the explosive charge in the firingchamber is under a high degree of compression greater than that tendingto open the valve, thereby holding said valve closed during the eX-plosion, the valve 15 will have been moved a quarter turn to close theports V19 and -21- and thereby cut off communication between the firingchamber and compression chamber and also between the carbureter andcompression chamber. As the piston begins and during its outward stroke,the valve 15 will have shifted rotarily to connect the ports 19 and -20,thereby causing the mixture to be drawn by suction of the piston head llfrom the carbureter into the compression chamber -9, it being understoodthat during this operation communication between the ports 20 and 2l iscut off. This induction of the mixture will continue until and a shorttime after the piston reaches the limit of its-suction stroke whereuponthe operation of the valve, as previously described, will be repeated.As the piston reaches the limit of its outward stroke, it will uncoverand permit the discharge of the spent gases through the exhaust port 14and this expulsion of the spent gases from the firing chamber will beaugmented by the inflowing mixture, which, it will be remembered, wasunder compression at the inlet port sufficient to open the valve byreason of the fact that the pressure resistance to such openinggradually reduces as the piston reaches the end of its out-stroke andparticularly when the exhaust port is opened.

It is now evident that the pressure of the, mixture tending to open theinlet valves will be suificient to hold either of said valves openduring a considerable part of the compression stroke of thecorresponding piston after the latter has closed its exhaust port anduntil the counteracting pressure of the compressed charge is equal to orexceeds that of the inflowing mixture whereupon such valve will beclosed and will remain closed during the firing of the charge and untilthe pressure in the firing charmber is reduced by the out-stroke of thepiston to a degree less than that of the inflowing mixture which willtake place as soon as or beforethe piston begins to uncover the exhaustport at which time the valve will be again opened to admit a freshcharge to the firing chamber.

The operation of each piston is substantially the same as that ustdescribed owing to the fact that the conduits -17 communicate with allof the valve chambers of the intake valves and also with all of thevalve chambers of the inlet valves.

In order to maintain a more uniform pressure at the inlet, I haveprovided the connection between. the intake ports and inlet ports withan auxiliary pressureequalizing chamber -26 which may also be termed apressure reservoir in which a portion, at least, of the highlycompressed mixture is temporarily trapped, thus reducing the initialpressure and keeping the reduced pressure more constant and in a compactmass inthe head of the firing chamber while the inlet valve is open.

Owing to the fact that the mixture is introduced into the firingchambers of the cylinders under considerable pressure while the pistonsare approaching the limits of their outward strokes, there is liabilityof such mixture taking a direct course through the firing chamber to theexhaust and not thoroughly scavenging the cylinder from the spent gaseswhen the exhaust is opened.

In order to more thoroughly expel the spent gases from the firingchamber, I have provided each cylinder with an inwardly projectingflange -30 having a concaved deflecting surface facing the inlet port sothat, when the inlet valve is opened, the influx of the mixture isdiverted into the pocket formed by the concaved surface and is therebydeflected toward the center of the firing chamber to form a cushioncovering the entire area of the interior of the cylinder adjacent theinlet traveling toward the exhaust and thereby more effectivelyexpelling the spent gases. This flange may extend only part way acrossthe cylinder, as shown more clearly in Figs. 2 and 5, in which case itwill be on the same side as the exhaust port or it may extend entirelyaround the interior of the cylinder thus forming anannular flange asshown in Fig. 7. In either of these forms, however, the flange serves toprevent direct passage of the mixture along the sides of the cylinder tothe exhaust by concentrating such mixture at the center engines aresubstantially the same as for the .chambers for the intake valves withthe inlet ports is located between the cylinders instead of at one sidethereof. The valves and valve chambers for these two-cylinder 8Ofour-cylinder engines except that they have but two in-take valvesinstead of four, but the conduits leading from the intake valve chambersto the inlet ports are provided with a pressure-equalizing chamber -26'for the same purpose as the chamber 26 previously described, saidpressure-equalizing chambers being located at one side of the mainpassage between the intake and inlet ports so as to avoid condensationand consequent imperfect mixture.

In Fig. 8 I have shown a slightly modifiedform of pressure-equalizingchamber 31 having branches 32 connected directly to the valve chambersas 33 for the intake valves instead of connecting such equalizingchamber to the conduit 17 as shown in Figs. 1, 2 and 3, the conduits-17- being kept separate at their crossings by a partition between themas shown more clearly in Fig. 2 although both conduits communicate atthis point with the equalizing chamber 26.

In Fig. 2, I have shown the cylinder as provided with an auxiliaryexhaust or pressure relief port 14' located about midway of thecompression stroke of the piston between the main exhaust port 14- andbaffle plate 30. at the same side of the cylinder as the main exhaustport and connected by a conduit -18 with the manifold exhaust pipe 18 soas to discharge thereinto, said conduit being provided with a rotaryvalve -40 which is normally closed when the engine is running under fullload or high speed but is adapted to be opened at will by any suitableoperating mechanism when the engine is running light or idle to allowpartial exhaust of the spent gases before the main exhaust is opened and1 thereby reducingthe vibration of the engine and also to induce thenoise incidental to the use of a single exhaust port as 14..

Another important feature of my invention consists in the intersectingcross connections 1 7- connecting opposite pairs of cylinders, eachconnection serving as a means of communication between the intake portsof one pair of cylinders with the inlet ports of the opposite pair sothat the compression stroke of the cylinder of either pair will force acharge of the. explosive mixture into the firing chamber of one of thecylinders of the other pair and will also force a part of such chargeinto the firing chamber of the first named cylinder during a part of itscompression stroke after its exhaust port is closed or until thepressures at opposite sides of the inlet valve of such cylinder isequal, it being understood that a quantity of the explosive mixture isalways maintained under pressure at all of the inlet valves and that,while the piston of one of the cylinders is passing through its entirecompression stroke, the inlet valves of the other cylinder will besuccessively opened by the pressure of the mixture produced by thatpiston, this operation being repeated during the com-- pression strokeof each of the pistons.

What I claim is:

1. In a two-cycle internal combustion engine, a pair of cylinders havingvalvecontrolled intake and inlet ports and pistoncontrolled exhaustports, and a constantly open passage connecting the 'valve chambers ofboth the intake and inlet valves, valves for said intake and inlet portsand a pressure equalizing chamber in direct and constant communicationwith said passage, said valve for the-inlet port being spring closed andopened only by gas pressure in the passage.

2. A two-cycle internal combustion engine having its cylinder providedwith constantly connected intake and inlet valve-chambers and apiston-controlled exhaust port, valves in said chambers, and a flange onthe interior of the cylinder having a concave side facing the inlet totemporarily pocket a portion of the infiowing mixture and prevent itsdirect flow from the inlet to the exhaust port, said inlet valve beingopened only by the gas pressure in said passage.

3. A two-cycle internal combustion engine comprising separate pairs ofcylinders, each having an intake port, an inlet port, an exhaust port,and a piston controlling the exhaust port, synchronized valves for theintake ports and conduits each leading from the valve chamber of onepair of cylinders to the inlet port of the other pair of cylinders, saidinlet ports having self-closing valves opened only by the gas pressurein the conduits leading thereto.

4. A two-cycle internal combustion engine comprising separate pairs ofcylinders, each having an intake port, an inlet port, an exhaust portand a piston controlling the ex- I haust port, synchronized" valves forthe intake ports, conduits each leading from the valve chamber of onepair of cylinders to the inlet port of the other pair of cylinders, andan equalizing chamber communicating with conduits, said inlet portshaving separate self-closing valves opened only by the pressure of fuelin the conduit leading thereto.

5. In a two-cycle internal combustion engine, a cylinder having an inletport and an exhaust port and a piston controlling the exhaust port, saidcylinder having an auxiliary port with sufficient pressure to hold theinlet valve open during a portion of the compression stroke of thepiston after the exhaust port is closed by said piston.

6. In a two-cycle internal combustion engine, a cylinder having an inletport in its head end and an exhaust port in one side, a piston movablein the cylinder and controlling the exhaust port said cylinder having anauxiliary exhaust passage between the exhaust port and inlet port and inthe same side of the cylinder as the exhaust port, and a valve in saidpassage, said inlet port having a self-closing valve in combination withmeans for introducing the fuel into the inlet port with sufiicientpressure to hold the inlet valve open during a portion of thecompression stroke of the piston after the latter has closed the exhaustport.

7. In a two-cycle internal combustion engine, a cylinder having an inletport in its head end and an exhaust port in one side, a piston movablein the cylinder and controlling the exhaust port, a baflie plate in a di-rect line between the inlet port and exhaust port to prevent the directpassage of the inflowing mixture to the exhaust port, said cylinderhaving an auxiliary exhaust passage between the .exhaust port and baffleplate, and a valve in said passage, said inlet port having aself-closing valve in combination with means for introducing the fuelinto the inlet port with suflicient pressure to'open the inlet valveduring a portion of the compression stroke of the piston after theexhaust port is closed.

8. In a two-cycle internal combustion engine, the combination of acylinder having a firing chamber and a relatively larger fuelcompression chamber, said chambers having respectively a fuel intakeport and a fuel 'inlet port, the firing chamber being provided with anexhaust port and an auxiliary exhaust passage between the exhaust portand the head of the cylinder, a conduit connecting the intake port ofthe compression chamber with the fuel inlet port of the firing chamber,a valve controlling the passage of fuel through said conduit, connectedpistons moving in said chambers, a valve for the exhaust passage, and aseparate self-closing valve for the inlet port opened only by thepressure of the fuel passing through said conduit.

9, In a two-cycle internal combustion engine, the combination of acylinder having a chamber, a valve controlling the passage of fuelthrough said conduit, connected pistons moving in said chambers, a valvefor the exhaust passage, and a separate self-closing Copies of thispatent may be obtained for five cents each, by addressing the valve forthe inlet port opened only by the pressure of the fuel passing throughsaid 15- con'duit, said conduit having a pressureequalizing chamber intowhich a portion of the fuel under pressure is forced when the valve forthe intake port is opened.

In witness whereof I have hereunto set 20 my hand this 9th day ofNovember, 1912.

DANIEL M. TUTTLE.

Witnesses:

H. E. CHASE, EVA E. GREENLEAF.

Commissioner of Patents,

Washington D. G.

